DSO's are definately not possible with a Dob unless you want trailing stars in the image.
With a Dob, you can wack in a webcam like a ToUcam and get pretty good Planet and Moon images almost straight away.
How I started with my ToUcam was to have the object (the Moon for example) drift across the Field of View in my 12" dob. There was enough info in that drifting video to stack it and get good results.
DSO's definately need tracking and any DSO over about 20 seconds really should be Guided as well.
Astrophotography is a steep long learning curve, but geez it's fun
